System LEDs
Each board led has a directory in /sys/class/leds. By default the LEDs use the following triggers:
| LED | Trigger |
|---|---|
| wifi_active | phy0tx (WiFi Tx) |
| bt_active | hci0tx (bluetooth Tx) |
| user_led1 | heartbeat |
| user_led2 | mmc0 (disk access, eMMC) |
| user_led3 | mmc1 (disk access, microSD card) |
| user_led4 | CPU core 0 active(not used) |
To change a user LED you can do the following as a root user:
# echo heartbeat > /sys/class/leds/<led_dir>/trigger make a LED flash
# cat /sys/class/leds/<led_dir>/trigger show triggers
# echo none > /sys/class/leds/<led_dir>/trigger remove triggers
# echo 1 > /sys/class/leds/<led_dir>/brightness turn LED on
# echo 0 > /sys/class/leds/<led_dir>/brightness turn LED off